A construction machine such as a shovel is provided with a muffler including an exhaust-gas cleaning apparatus for removing toxic substances in exhaust gas discharged from a diesel engine as a standard specification. For example, WO2010/026864 (Patent Literature 1) discloses an exhaust-gas cleaning apparatus including an upstream cylinder body, a downstream cylinder body, and a filter cylinder body interposed between the upstream cylinder body and the downstream cylinder body. In the filter cylinder body, a DPF (Diesel Particulate Filter) is provided to remove a PM (Particulate Matter) and the like included in exhaust gas. A silencer cylinder body of an outflow pipe is inserted into the downstream cylinder body.
When the construction machine including such an exhaust-gas cleaning apparatus is operated in a region without an exhaust gas regulation, there is a possibility that sulfur contained in fuel used in the region exceeds an allowable content of the exhaust-gas cleaning apparatus to thereby disable the DPF from being regenerated.
Exchanging the engine to an engine of an exhaust gas non-regulation specification as measures against the problem requires design and manufacturing of a new engine corresponding to a device layout in an engine room or substantial remodeling and component replacement on a construction machine main body side, involving respective marked increases in costs and man-hours.